In this patent application, we will use the term “working” a material to mean processes which involve friction in changing the shape of a material such that heat is generated and the temperature of the material is increased, either overall or at the specific place where the working is conducted. Examples of processes which would fall within our meaning of this term, not intending to be limiting, would include drilling, cutting with a saw, machining, lathing and polishing. During the working of a material, heat is generated. This can cause a change in dimensions, softening of working tools and galling and possible binding of tools during working. In order to keep the material and the working tools at a lower temperature and to carry away chips and shards from the working process, a cutting fluid is often used. This is a fluid which is allowed to flow over the surfaces being worked. It can carry away heat, keep the temperature of the working surfaces in controlled range and carry away shards and chips generated in working the material.
A class of fluids exists called reverse thermal fluids. This class of fluids is characterized in that they have a lower viscosity at a lower temperature, then show an increase in viscosity as the temperature is increased. The temperature range over which the viscosity shows this viscosity is called the transition temperature. For some reverse thermal fluids, the degree of viscosity increase can be quite large—over an order of magnitude or more—and the transition temperature range can be narrow—in the range of 5 to 10 degrees C. More information about reverse thermal fluids is given below.
We have invented a process for working materials in which a reverse thermal fluid is used as a cutting fluid. The fluid is initially below its transition temperature and is allowed to flow onto the material being worked. As the fluid comes into intimate thermal contact with the material being worked, the fluid temperature increased above the transition temperature and the fluid viscosifies and remains in contact with the parts being worked. This reduces the volume of cutting fluid being used and so decreases the quantity of fluid which needs to be treated as contaminated waste. It increases the ability of the cutting fluid to control the temperature of the surfaces being worked. If the cutting fluid contains expensive anti-rust additives or other additives, it reduces the quantity of these expensive additives which must be used. During the process of working materials, an article of manufacture is formed in which the surfaces being worked are in intimate contact with the reverse thermal fluid at a temperature above its transition temperature.
This invention is the first to propose the use of a reverse thermal fluid as a cutting fluid. It is the first to propose an article of manufacture in which a surface being worked is in intimate contact with a reverse thermal fluid at a temperature above its transition temperature. It is the first to propose the inclusion of antirust additives or other additives to a reverse thermal fluid to improve its performance as a cutting fluid. Improvements made in the current invention can result in unprecedented performance advantages in working of materials and in the reduction of fluids which must be handled as contaminated waste.